GB2206525A - Orientated polypropylene films - Google Patents

Orientated polypropylene films Download PDF

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Publication number
GB2206525A
GB2206525A GB08716027A GB8716027A GB2206525A GB 2206525 A GB2206525 A GB 2206525A GB 08716027 A GB08716027 A GB 08716027A GB 8716027 A GB8716027 A GB 8716027A GB 2206525 A GB2206525 A GB 2206525A
Authority
GB
United Kingdom
Prior art keywords
polypropylene
film according
polypropylene film
films
polymeric
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08716027A
Other versions
GB8716027D0 (en
GB2206525B (en
Inventor
Matthew John Marsh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Akzo Nobel Films Holding Ltd
Original Assignee
Courtaulds Films and Packaging Holdings Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Courtaulds Films and Packaging Holdings Ltd filed Critical Courtaulds Films and Packaging Holdings Ltd
Priority to GB8716027A priority Critical patent/GB2206525B/en
Publication of GB8716027D0 publication Critical patent/GB8716027D0/en
Priority to EP88306179A priority patent/EP0298731A1/en
Priority to PCT/GB1988/000533 priority patent/WO1989000105A1/en
Priority to AU19695/88A priority patent/AU1969588A/en
Publication of GB2206525A publication Critical patent/GB2206525A/en
Application granted granted Critical
Publication of GB2206525B publication Critical patent/GB2206525B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/005—Shaping by stretching, e.g. drawing through a die; Apparatus therefor characterised by the choice of materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B32B15/085—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10—Homopolymers or copolymers of propene
    • C08L23/12—Polypropene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2023/00—Use of polyalkenes or derivatives thereof as moulding material
    • B29K2023/10—Polymers of propylene
    • B29K2023/12—PP, i.e. polypropylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0065—Permeability to gases
    • B29K2995/0067—Permeability to gases non-permeable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0077—Yield strength; Tensile strength
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0088—Molecular weight
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B38/00—Ancillary operations in connection with laminating processes
    • B32B38/0012—Mechanical treatment, e.g. roughening, deforming, stretching
    • B32B2038/0028—Stretching, elongating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/514—Oriented
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2311/00—Metals, their alloys or their compounds
    • B32B2311/24—Aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2323/00—Polyalkenes
    • B32B2323/10—Polypropylene

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Description

2 0 5 2 5 1.
1 1 t 1 - 1 ORIENTED POLYPROPYLENE FILM S This invention concerns oriented polypropylene films.
It is known to produce oriented polypropylene films. In order to provide the films with various properties, for example heat sealability, one or more layers can be applied to either or both sides of the films. Such layers can be formed by co-extrusion of the material for forming the layers v 1 with the polypropylene. The resultant films have found wide acceptance as packaging materials.
According to the present invention there is provided an oriented polypropylene film, the polypropylene used to prepare the film having a melt flow index of 1.5 to 18. 0 and a polydispersity index of from 3.0 to 5.5.
The polypropylene films of the present invention have particularly good physical properties compared with known oriented polypropylene films. Films of the present invention have shown increased rigidity, increased tensile strength, increased impact resistance and decreased water vapour transmission rates compared with conventional films produced from polypropylene other than as specified for films of the present invention.
The melt flow index of the polypropylene should be from 1.5 to 18.0 as measured by ASTM method D1238 at 2300C (condition L), and it is preferably from 2.5 to 6.0.
The polydispersity index of the polypropylene should be from 3.0 to 5.5 as measured by the method of G. E. Zeichner and P. D. Patel P'A comprehensive evaluation of polymer melt rheologyll, Proceedings of 2nd World Congress of Chem. Eng., Vol. 6, page 333, Montreal, 1981), preferably from 3.5 to 4.2. The polydispersity index of a polymer is a measure of the spread of molecular weight distribution in the polymer, and it is inversely proportional to the crossover modulus of the polymer under oscillatory shear.
Polypropylene having the desired rheological properties can be produced by modifying the molecular, weight distribution of known grades of polypropylene. In particular, the molecular weight range of a given grade of polypropylene can be reduced by selectively reducing the molecular weight of the higher weight components. This can be effected, for example, by reaction with peroxides.
Polypropylene films of the present invention can be produced using conventional orientation techniques, and in general using sequential stretching in the machine and transverse directions. Particularly good physical properties can be imparted 4 to films of the present invention using machine direction stretch ratios in excess of 5.5: 1, preferably from 6.5 to 8.0: 1 and subsequent transverse direction stretch 1, preferably from 12 to 13.5 increases of greater than 80 1, 2 ratios in excess of 10 1. Film area and preferably from 95 to 110: 1, have given films with good rigidity, tensile strength and impact strength, and reduced water vapour transmission rates.
Film rigidity has been increased by at least 20% in the machine direction and by at least 10% in the transverse direction, machine direction tensile strength has been increased by at least 40%, and impact strength has been increased by at least 50%, all compared with conventional oriented polypropylene films made from polypropylene homopolymer having in particular a polydispersity index outside the range specified for the present invention. Water vapour transmission rates reduced by at least 15% have also been observed.
Films of the present invention can also include additives which modify their frictional and/or antistatic properties, for example silicones and/or amides and/or other additives known in the ar t.
Polypropylene films of the present invention can be provided with any of the coatings and/or layers known in the art for polypropylene films and for the purposes of providing a similar effect.
Sealability.can be provided by a cold seal layer, for example of an elastomeric composition, or b a hot seal layer, for example a polymeric layer containing units derived from at least one of ethylene, propylene and butene. Heat sealability can also be provided by using layers of copolymers of vinylidene chloride, for example with vinyl chloride and/or methyl methacrylate. Polymeric layers containing units derived from vinylidene chloride and/or acrylics can also be used as primer layers, for example to aid printability.
Antiblock can be imparted by the inclusion of particulate materials in the coatings or layers, for example silica can be included.
While it is often preferred to produce heat seal and other layers on a polypropylene base layer by - 6 co-extrusion or extrusion coating, it is possible, and in some cases it is preferable, if not essential, to produce layers on the polypropylene using aqueous dispersions or solutions of the material for forming the desired layer.
Subsequent to orientation, the films of the present invention can, if desired, be subjected to further processing steps. For example, one or both sides of the film can be subjected to corona discharge in air or other gases or to,flame treatment, both being used to enhance the wettability and/or the printability of the resultant film.
Polypropylene films of the present invention can be provided with metal layers, e.g. of aluminium, for example a metal layer can be deposited by a vapour technique or by lamination to a metal film using an adhesive layer. Such techniques are well known in the art for polypropylene films.
It is also possible to laminate polypropylene films of the present invention to other polymeric films to provide various effects. For example, it is possible to protect a layer of printed t 1 1 indicia by lamination with the indicia protected within the laminate.
Lamination using metal and/or other layers can also be used to modify the properties of the resultant composite film, for example reduce their permeability to oxygen and/or water vapour can be achieved, for example as is known in the art.
The following Examples are given by way of illustration only:Example 1 A propylene homopolymer of melt index 4.0 and polydispersity index 4.4 was extruded through a flat die onto a water immersed chill roll to produce a flat sheet of 3.Omm thickness. The sheet is then re-heated to 1200C and stretched 7.5: 1 in the machine direction (MD). The stretched sheet is then further heated to about 1600C and stretched 15: 1 in the transverse direction (TD) using a stenter oven. The film was relaxed in the transverse direction, cooled, and wound up. The resultant film had the properties shown in Table 1 which also shows those for a conventional oriented polypropylene film produced from a polypropylene resin of melt index 3.0 and polydispersity index 5.9 stretched 5.0: 1 and 9.0: 1 in the machine and transverse directions respectively. Example 2 A film was produced using the method of example 1 but using a polypropylene homopolymer of melt index 5.0 and polydispersity index 3.6 and coextruding the homopolymer with a propylene- ethylene copolymer to form outer layer(s) on both sides constituting about 7% of the total film thickness. This film was stretched 7.7: 1 in the machine direction and 12.5 in the transverse direction. The properties of the film are shown in Table i : 1 - 9 TABLE 1
1.
Property Conventional Example Example Polypropylene 1 2 film Thickness (micron) 30 30 30 Rigidity (g/CM) MD/TD 1.3/2.3 1.7/2.8 1.9/2.6 Modulus (MPa) MD/TD 1400/2500 2300/4050 2450/3900 Tensile strength (MPa) MD/TD 120/260 175/260 190/265 Impact strength2 (kg/cm) 60 122 133 WVTRI(g/m' 24 Hr.) 4.3 3.5 3.5 Handle-o-meter method - British Standard 2782 method 332 2. Frank method 3. Water vapour transmission rate 381C 90% RH

Claims (12)

-CLAIMS
1. An oriented polypropylene film, the polypropylene used to prepare the film having a melt flow index of 1.5 to 18.0 and a polydispersity index of from 3.0 to 5.5.
2. A polypropylene film according to claim 1, wherein the polypropylene has a melt index of 2.5 to 6.0.
3. A polypropylene film according to either of the preceding claims, wherein the polypropylene has a polydispersity index of from 3.5 to 4.2.
4. A polypropylene film according to any of the claims stretched in excess of 5.5: 1 in the machine direction.
5. A polypropylene film according to any of the preceding claims stretched in excess of 10: 1 in the transverse direction.
6. A polypropylene film according to any of the preceding claims, having a total area stretch ratio in excess of 80: 1.
7. A polypropylene film according to claim 6, having a total area stretch ratio of from 95 to 110:1 nrecedine -1 I 1
8. A polypropylene film according to any of the preceding claims, having at least one polymeric layer thereon.
9. A polymeric film.according to claim 8, having a polymeric layer on each surface.
10. A polypropylene film according to any of the preceding claims, having a heat sealable layer thereon.
11. A polymeric film according to any of the preceding claims, having at least one metal layer.
12. A polypropylene film according to any of the preceding claims, laminated to a further film comprising a polymeric layer.
Published 1985 at The Patent Offire. State House. 66'71 High Holborn, London WC1R 4TP- Fuxther copies maybe obtained from The Patent Office, 1
GB8716027A 1987-07-08 1987-07-08 Orientated polypropylene films Expired - Lifetime GB2206525B (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
GB8716027A GB2206525B (en) 1987-07-08 1987-07-08 Orientated polypropylene films
EP88306179A EP0298731A1 (en) 1987-07-08 1988-07-07 Voided polypropylene films
PCT/GB1988/000533 WO1989000105A1 (en) 1987-07-08 1988-07-07 Voided polypropylene films
AU19695/88A AU1969588A (en) 1987-07-08 1988-07-07 Voided polypropylene films

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8716027A GB2206525B (en) 1987-07-08 1987-07-08 Orientated polypropylene films

Publications (3)

Publication Number Publication Date
GB8716027D0 GB8716027D0 (en) 1987-08-12
GB2206525A true GB2206525A (en) 1989-01-11
GB2206525B GB2206525B (en) 1990-03-07

Family

ID=10620279

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8716027A Expired - Lifetime GB2206525B (en) 1987-07-08 1987-07-08 Orientated polypropylene films

Country Status (4)

Country Link
EP (1) EP0298731A1 (en)
AU (1) AU1969588A (en)
GB (1) GB2206525B (en)
WO (1) WO1989000105A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995001474A1 (en) * 1993-06-29 1995-01-12 Fiberweb North America, Inc. Nonwoven webs and method of making same

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3937941A1 (en) * 1989-11-15 1991-05-16 Hoechst Ag ROTARY WRAPPING FILM MADE OF POLYPROPYLENE
DE4030669A1 (en) * 1990-09-28 1992-04-02 Hoechst Ag BIDDEN SEALABLE, BIAXIALLY ORIENTED POLYOLEFINE MULTILAYER FOIL WITH VERY GOOD OPTICAL PROPERTIES
CN1037183C (en) * 1991-07-13 1998-01-28 中国科学院化学研究所 Polypropylene resin combination and its preparing process

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1210176A (en) * 1981-06-15 1986-08-19 Michael T. Morman Degradation of polypropylene for future improved processability
JPS60149434A (en) * 1984-01-18 1985-08-06 Mitsui Toatsu Chem Inc Biaxially stretched polypropylene film
DE3521328A1 (en) * 1985-06-14 1986-12-18 Hoechst Ag, 6230 Frankfurt SYNTHETIC GIFT PAPER
JPS62115049A (en) * 1985-11-14 1987-05-26 Sumitomo Chem Co Ltd Impact-resistant polypropylene composition

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995001474A1 (en) * 1993-06-29 1995-01-12 Fiberweb North America, Inc. Nonwoven webs and method of making same

Also Published As

Publication number Publication date
GB8716027D0 (en) 1987-08-12
AU1969588A (en) 1989-01-30
EP0298731A1 (en) 1989-01-11
WO1989000105A1 (en) 1989-01-12
GB2206525B (en) 1990-03-07

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19920708